Image forming apparatus

Abstract

An image forming apparatus includes: an image carrier unit that is attachable to and removable from an apparatus body and that includes an image carrier; a development roller that passes toner to the image carrier when located in a position near the image carrier; an operation portion that moves, when operated, between a block position in which the operation portion blocks detachment of the image carrier unit from the apparatus body and an allowance position in which the operation portion allows detachment of the image carrier unit from the apparatus body, the development roller moving toward the image carrier in association with a movement of the operation portion to the block position, and the development roller moving away from the image carrier in association with a movement of the operation portion to the allowance position; and a positioning portion that positions the image carrier unit relative to the apparatus body in an attachment-removal direction of the image carrier unit when the operation portion is moved to the block position.

What is claimed is: 
     
         1 . An image forming apparatus comprising:
 an image carrier unit that is attachable to and removable from an apparatus body and that includes an image carrier;   a development roller that passes toner to the image carrier when located in a position near the image carrier;   an operation portion that moves, when operated, between a block position in which the operation portion blocks detachment of the image carrier unit from the apparatus body and an allowance position in which the operation portion allows detachment of the image carrier unit from the apparatus body, the development roller moving toward the image carrier in association with a movement of the operation portion to the block position, the development roller moving away from the image carrier in association with a movement of the operation portion to the allowance position; and   a positioning portion that positions the image carrier unit relative to the apparatus body in an attachment-removal direction of the image carrier unit when the operation portion is moved to the block position.   
     
     
         2 . The image forming apparatus according to  claim 1 ,
 wherein, when the operation portion is moved to the allowance position, the positioning portion cancels positioning of the image carrier unit relative to the apparatus body.   
     
     
         3 . The image forming apparatus according to  claim 2 ,
 wherein the positioning portion positions the image carrier unit relative to the apparatus body and cancels positioning of the image carrier unit relative to the apparatus body with direct or indirect transmission of a moving force of the operation portion.   
     
     
         4 . The image forming apparatus according to  claim 3 ,
 wherein the operation portion includes a gripper member to be held by an operator and a shaft member that rotatably supports the gripper member, and   wherein part of the positioning portion is directly attached to the shaft member.   
     
     
         5 . The image forming apparatus according to  claim 1 ,
 wherein the positioning portion includes a recess formed in the image carrier unit and set back in a cross direction that crosses the attachment-removal direction of the image carrier unit, and a protrusion that moves together with the operation portion and that is inserted into and removed from the recess.   
     
     
         6 . The image forming apparatus according to  claim 5 ,
 wherein the operation portion includes a gripper member to be held by an operator and a shaft member that rotatably supports the gripper member and that extends in the attachment-removal direction,   wherein the protrusion is attached to the shaft member, and protrudes in a radial direction of the shaft member,   wherein the recess is recessed in the cross direction to allow the protrusion that rotates to be inserted into and removed from the recess,   wherein the recess has a first guide surface that guides the protrusion to the recess during insertion of the protrusion into the recess, the first guide surface being inclined with respect to the cross direction to increase an opening width of the recess, and   wherein the protrusion has a second guide surface that guides the protrusion to the recess and that is allowed to come into contact with the first guide surface during insertion of the protrusion into the recess, the second guide surface being inclined with respect to a circumferential direction of the shaft member.   
     
     
         7 . An image forming apparatus, comprising:
 image carrier means for being attached to and removed from an apparatus body, and including an image carrier;   development roller means for passing toner to the image carrier when located in a position near the image carrier;   operation means for, when operated, moving between a block position in which the operation means blocks detachment of the image carrier means from the apparatus body and an allowance position in which the operation means allows detachment of the image carrier means from the apparatus body, the development roller means moving toward the image carrier in association with a movement of the operation means to the block position, and the development roller means moving away from the image carrier in association with a movement of the operation means to the allowance position; and   positioning means for positioning the image carrier means relative to the apparatus body in an attachment-removal direction of the image carrier means when the operation means is moved to the block position.